CFC and LTC-IC activity of DC mPB cells. (A) Mean plus or minus SEM frequency of CFCs expressed per 10³ CD34⁺ cells in the 5 DC mPB samples (black bar) and in 5 healthy donors (□). Values shown are the sum of the total erythroid (BFU-E), granulopoietic (CFU-GM), and multilineage (CFU-GEMM) progenitors detected in these assays. (B) Measurements of the average size (nucleated cell content) of the colonies produced in panel A. Values shown are the mean plus or minus SEM. Each value was calculated by dividing the total number of cells measured in the 2-week CFC assay cultures (as described in “Methods”) by the total number of colonies scored in those assay cultures. (C) Mean plus or minus SEM of the number of LTC-ICs expressed per 10⁴ DC (■) and normal (□) CD34⁺ mPB cells assayed. (D) Photomicrographs of typical colonies detected in the CFC assays of normal (left panel) and DC (right panel) cells.